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Laser-based radiation detector allows testing from a safer distance

A multi-institutional team of physicists and engineers has developed a laser-based radiation detection system that operates from as far away as 10 meters and perhaps farther. Their research is in the journal Â鶹ÒùÔºical Review Applied.

Working with nuclear material, whether in creating weapons or energy, requires monitoring radiation levels to ensure the safety of workers. However, most detectors only allow for testing in close proximity to the source, which means a worker can be in danger of overexposure before they know it has happened. In this new study, the team assigned themselves the goal of developing a new type of system or device that could be used to test from much farther away.

The team started by noting that radiation interacts with molecules in the air around it, resulting in the creation of free electrons, so it should be possible to measure the energy of those electrons using a laser beam. In testing their ideas, they found that firing a laser into irradiated air did lead to molecule collisions, which produced free electrons.

They then found that firing a laser into the same air space also gave the electrons more energy when struck and more again when they continued on and struck air molecules. The process cascaded, with the result being the creation of a small amount of plasma—they describe it as being like a tiny lightning ball. Other lasers fired at the plasma balls bounced back, allowing their energy to be measured. This phenomenon could be used as a way to detect radiation levels from a distance.

The team built a small system based on their ideas and found it capable of detecting radiation levels at 10 meters—a distance that was restricted by the size of the room in which they were working. They suggest it is likely a device using the new technology could be used to detect radiation levels up to 100 meters.